you want a solvent ....many liquids dissolve grease ...petrol the fuel used in motorbikes and petrol powered cars ....in garages this is used to clean greasy car parts ,like carburetors , then the petrol is thrown away , it's very cheap ....

alcohol can also be used or acetone ...

These are not easy to make ...you could make alcohol .... ferment sugar solution with yeast , then distill